Permanent 'live' to boiler SL. Pump running 24/7

[cocjh1]

Hi,

Wondered if anyone could help with the following. I suspect I've got a broken CH motorised valve head, resulting in pump running 24/7.

With CH and HW off at timer, I'm still getting live to SL in boiler (neon1 on). If I unplug electrics to the CH motorised head the pump goes off (neon1 off). The system appears to operate fine with CH electrics unplugged, and I can happily control the HW supply.

To try and test things I swapped the CH and HW heads over, and likewise, their electric plugs. Upon enabling power the 3amp fuse in mains isolation switch blows!?

Swapped things back and replaced 3amp fuse. The CH valve is still controllable via the timer, ie, turning the room stat temp up and down, opens and closes the CH valve.

Does it sounds like a broken valve head? Any help/advice appreciated. Why would the fuse blow when placing 'suspect' broken motorised head on HW and not on CH?

Thanks,
Chris

Notes:
Boiler: Glow Work ultimate 70FF
Timer: Sunvic 207XL
Valves: BGMVSP-2 (555212)

Everything working just find until two evenings ago. No work has been undertaken recently and system is ~12 years old.

 

[seco services]

you say the valve is still opening and closing by the room stat.
but your still getting SL at the boiler/pump when valve closed.

is the orange wire from the CH valve live ?
if so the m/switch is stuck in the valve.

To try and test things I swapped the CH and HW heads over, and likewise, their electric plugs. Upon enabling power the 3amp fuse in mains isolation switch blows!?

must of wired it wrong.
otherwise it would just do the same as when it was on the CH valve.

 

[DeltaT]

Could be a jammed actuator head motor?? Well dodgy timer by the way. Hate to say it about a Scottish firm but these programmers are rubbish!!

 

[cocjh1]

is the orange wire from the CH valve live ?
if so the m/switch is stuck in the valve.

With both CH and HW off at timer, both valves are closed but orange wire from CH head remains live (high). Disconnecting orange wire causes pump to turn off. Must conclude a broken microswitch in CH motorised valve.

As a temporary fix until new head arrives I tried swapping the CH and HW heads over (can manually call for hot water etc.), but leaving the broken HW (old CH) head unplugged. Unfortunately the system won't control the CH head with the HW unplugged, and plugging in the HW head blows the 3amp fuse.

Not sure how they are wired but there must exist a relationship between CH and HW somehow..

Ta,
Chris

 

[sambotc]

Is there a white wire connected anywhere?

 

[cocjh1]

I thought the motorised heads were simply plug compatible, put whatever monkey wired the house up 12 years ago decided against that! Just open the two plugs up and noticed wiring is different!

Now have CH working on timer, and HW under manual control till replacement part arrives.

Thanks everyone for your input.

Ta,
Chris[/img]